| Objective1. To define the anatomical type of pulmonary vein by the DSCT scan, and to discuss the relationship between its normal variant and atrial fibrillation.2. To study the variation of pulmonary venous ostia during full time phase by using ECG-gated DSCT, to measure the sizes of pulmonary vein ostia in atrial fibrillation and non-atrial fibrillation population and to analyze its relationship with atrial fibrillation.3. To comparative analyze the pulmonary vein imaging conditions by pulmonary vein angiography during atrial fibrillation radiofrequency catheter ablation and DSCT, to introduce the clinical applications of the CARTO-Merge technique.Materials and methods1. The general information1.1Study of pulmonary venous anatomical classification by DSCT140patients (including100patients without atrial fibrillation and40patients with atrial fibrillation) underwent the pulmonary vein imaging of DSCT coronary artery imaging sequences. In100patients without atrial fibrillation patients, there were65male and35female, average age was58.23±10.16years old. Its criteria for exclusion: mediastinal and pulmonary masses, fibrosis, consolidation, atelectasis, pericardial and pleural effusion, congenital heart disease, rheumatic heart disease, coronary heart disease, heart failure can influence the pulmonary venous disease, cardiac and renal dysfunction and iodine contrast medium allergic, obvious arrhythmia, respiratory breath-hold adverse, unable to cope with the scan. The atrial fibrillation patients include25male and15female, their average age was55.76±11.24years old.1.2Diameter measurements of pulmonary vein ostia by DSCT90cases classified as "standard" type in the first part of the pulmonary vein anatomical phenotyping was chosen as the research objects, in which there are64patients without atrial fibrillation,26cases with atrial fibrillation. We randomly collected20cases from these "standard" patients with right superior pulmonary vein (RSPV) as an example for analysis, and study the variation of pulmonary vein diameter during cardiac cycle.1.3Contrast analysis of DSCT and pulmonary vein angiography34patients of atrial fibrillation group from the second part underwent pulmonary vein angiography in the treatment of radiofrequency ablation. There were20male and14female, age ranged from14to80year old, average age was (58.23±10.36) years old.2. Instruments and MethodsInstruments and contrast medium:All patients were subjected to coronary heart imaging scan of the pulmonary vein with retrospective ECG gating techniques by dual-source CT (Somatom Definition, Germany, Siemens). Using the U.S MALLINCKRODT double tube high pressure syringe and Ultravist (370mgI/ml) non-ionic contrast agent.DSCT inspection methods:Fasting and water prohibition for4～8h are required before scanning. Routine breath training while using nitroglycerin aerosol spray sublingual (1of each spray) is also necessary, because it can keep a good breath in the scan with dilatation of the coronary artery and pulmonary vessels. Selected coronary artery imaging scan sequence (DS_Coronary CTA Routine_Adult), before scanning in accordance with the standard position connection kind conductance line in order to show normal heart rate. The scanning range of the tracheal bifurcation to the heart of the diaphragmatic surface of10mm under lOmm.CTA coronary artery imaging using artificial intelligence to trigger scanning, when the region of interest (ROI, located in the ascending aortic root) CT value reaches a preset value (100HU), and delayed3s boot scan. Double tube high pressure syringe was used for injection with superficial vein in the elbow to4.5～5.5ml/s flow of75～90ml non-ion iodic contrast medium(370mgI/ml), followed by injection of30ml saline. Data acquisition was performed at120kV and550mAs, tube rotation time was0.33s, pitch was0.20.5(according to the scanning rate changes automatically adjusting), detector collimating was32×0.6mm,the thickness of levels collection is64×0.6mm and the scanning time was7～11s.Methods of pulmonary vein angiography in radiofrequency catheter ablation: Using the Siemens AXIOM Artis dTA DSA flat system with a rotating collection CT imaging, contrast agents for Ultravist (370mgI/ml), local anesthesia for cardiac electrophysiology and catheter radiofrequency ablation. Conventional disinfection towel, successful puncture of the left subclavian vein and the right femoral vein, subclavian vein put6F coronary sinus electrode (CS), via the right femoral vein according to conventional methods of two puncture atrial septum was successfully through7.5F size of SL1long sheath into the left atrium, respectively in the left anterior oblique position45degrees and right anterior oblique position30degrees of pulmonary vein angiography, placing the Lasso electrode positioning of pulmonary vein potentials. After a long sheath into the navigation star cold normal saline perfusion head, from the pulmonary vein CARTO3D modeling are two electrical isolation of pulmonary veins, Lasso electrode to determine bilateral pulmonary vein atrial potentials whether electrical isolation completely.3. Image reconstruction, image post-processing and observation evaluation3.1Observation of pulmonary vein anatomical typeAfter the scan was completed, the best phase selection software of DSCT can automatically recombine optimal systolic (BestSyst phase) and diastolic (BestDiast phase) images. All the raw image data were transferred into Inspace software in BestSyst phase. These had used a variety of imaging methods which included volume rendering (VR), multiplanar reformation (MPR) and maximum intensity projection (MIP), etc. Used the Inspace software kit in the removal of skeletal pattern to extract pulmonary vein image, retained the integrity of the left atrium (LA) and left atrial appendage (LAA), proper cutting, rotating and mark, and observed the condition of pulmonary vein anatomy and contrast agent filling in LA, LAA for further analysis.3.2Measurement of pulmonary vein ostium in double phraseRaw data of20cases of "standard" pulmonary vein were firstly reconstructed from0%to100%with the interval of5%in all phrase, the slice thickness of reconstruction was1.5mm, interval was1.0mm, and convolution function value was B26f. After the reconstruction, the phase image data one by one into Inspace software, using Inspace bookmarks (Book Mark) derived bone pattern extraction preservation after pulmonary vein image, using Inspace4D advanced vessel analysis software (Advanced Vessel Analysis, AVA) in the vascular measurements ("Lumen to Vsssel" in measurement) planar reconstruction (MPR) images of the same level measurement of the right superior pulmonary vein (RSP V) at the opening of each phase of the long, the short diameter and cross section area of the measurement, statistics maximum and minimum values corresponding to the peak systolic and diastolic phase. Then, all standard pulmonary veins were post-processed in the two phases, included extracting pulmonary vein in VR images, measuring each pulmonary ostium for its long diameter, the short diameter, average diameter and cross-sectional area by the Inspace AVA, and the calculation of pulmonary vein orifice index (i.e. short size/length size) on branch vein, finally the data were statistically analyzed.3.3Contrast analysis of DSCT with pulmonary vein angiographyPulmonary vein and left atrium of DSCT image were reconstructed in75%phase, using Inspace4D vessel analysis software to measure average diameter of each pulmonary vein ostium in the same phase. Saved LAO45°and RAO30°projection images during intraoperative pulmonary vein angiography, using Leonardo image processing software to measure the diameter of pulmonary vein ostia. On two sets of measurements of pulmonary vein ostial diameters were statistically analyzed.4. Data recording and statistical analysis 4.1Summarized the domestic and foreign scholars on the pulmonary vein anatomy types, combined with clinical practice, pulmonary vein divided into standard type, open type, the common pulmonary vein side pulmonary vein type and mixed variant four types, as follows:(1) Standard type:Four pulmonary veins separately import left atrium, the distance between the ipsilateral pulmonary vein is>0.5cm.(2) Common ostium type:On the basis of the standard model to form the common pulmonary vein opening, on the same side, the inferior pulmonary vein distance is less than or equal to0.5cm.According to one common opening position is divided into left, right or bilateral common opening type3subtypes; and according to the ipsilateral pulmonary vein ostial in left atrium before without confluent divided into3subtypes, namely common openings (not confluent), shorter total stem (already confluent, opening from the pulmonary vein bifurcation is less than or equal to1.0cm long stem (total), has confluence, opening from the pulmonary vein bifurcation is more than1.0cm);(3) Vice pulmonary veins type:In the standard basis there is a new one or more pulmonary veins which called vice pulmonary vein. According to deputy pulmonary vein appears to be divided into3subtypes, namely the left side pulmonary vein, right side of pulmonary vein and the superior pulmonary vein;(4) Mixed variant:The pulmonary vein common ostium and vice pulmonary vein are existed together.Recorded separately without atrial fibrillation and atrial fibrillation patients pulmonary venous anatomic classification, statistics of the type and each subform combinations of emergence rate. The use of SPSS13statistical software to carry on the analysis, study a gross anatomical variation in the incidence and the mutation rate in AF group and without atrial fibrillation group, P<0.05considered significant difference.4.2Diameter measurement of pulmonary vein ostiumFor all the standard type of pulmonary vein ostial, recorded separately four pulmonary veins (LSPV, LIPV, RSPV, RIPV) of each measurement (long diameter, short diameter, average diameter, cross-sectional area, pulmonary vein ostium index) in patients with atrial fibrillation and without atrial fibrillation; recorded measurements of pulmonary vein ostial diameter of patients with AF in radiofrequency ablation by pulmonary vein angiography and DSCT. All data above measured by two professionals separately, and get the average value. Using SPSS13.0software package, all measurement data using said, research the measured values in AF group and without AF group had no statistical difference as well as the two kinds of pulmonary vein imaging measurements of pulmonary vein ostial diameter, P<0.05considered significant difference.Result1. Pulmonary venous DSCT anatomic classification and pulmonary venous variation and relationship of atrial fibrillationIn140cases, there were50cases found pulmonary vein anatomy variation, the total variation in the incidence was35.7%(50/140). In40patients with atrial fibrillation patients,26cases were standard type of pulmonary vein,14cases anatomic variation, the variation rate was35%(14/40);100patients without atrial fibrillation patients found in the standard type of pulmonary vein in64cases,36cases of anatomic variation, the variation rate was36%(36/100).Two groups of anatomic variation rate using χ2test,χ2=0.012, P=0.911, P<0.05, showed no significant difference in a with pulmonary vein variation rate between group of patients with atrial fibrillation and without atrial fibrillation.Among14cases of anatomic variation in group of atrial fibrillation,7cases appeared common pulmonary vein opening, accounted for50%of the total variance (7/14), which appeared on the left side, including4cases long stem,2cases short stem,1cases common opening but not confluent;6patients were found to show vice pulmonary veins, accounted for42.9%(6/14), all appeared on the right, except for1case with2branches of vice pulmonary veins, the remaining5cases appeared1branch of vice pulmonary vein; mixed variant was found in1cases, left pulmonary vein shorter total stem combined with right side pulmonary vein, accounted for7.1%(1/14). We found12types of variation, and common variant isoforms were long common trunk of left pulmonary vein, short common trunk of left pulmonary vein and single of the right middle pulmonary vein (RMPV), and the incidence rates of these above were10%versus7%,5%versus5%,12.5%versus13%between group of AF and non-atrial fibrillation. Using χ2test, P=0.510,1.0,1.0, P>0.05, various types of variation in incidence between group of AF group and non-atrial fibrillation were not statistically significant differences.2. The applied researched of pulmonary vein ostium diameter measurement by by using ECG-gated DSCT2.1Basing on a random sample of20cases of standard type pulmonary vein for study, we found that RSPV of standard pulmonary vein caliber showed periodic changing in a heartbeat cycle, the maximum average diameter and cross-sectional area appeared in the40%phase, the average diameter of RSPV was19.00±1.20mm, the average cross-sectional was293.70±41.29mm; minimum value appeared in the80%phase, the average diameter was17.33±1.14mm, the average cross-sectional area was238.00±39.62mm.2.2In group of atrial fibrillation and non-atrial fibrillation, using paired samples T test to analyze measurements of long diameter, short diameter, pulmonary vein ostium index and cross-sectional area during the two phrase of systolic and diastolic period,the difference was significant (P<0.01), i.e. measurements of systolic period were greater than those of diastolic period.Pulmonary vein diameter comparison between group of atrial fibrillation and non-atrial fibrillation using two independent samples T test to analyze, obtained the following results:(1) Between in group of atrial fibrillation and non-atrial fibrillation, the long diameter, short diameter and cross section area of the maximum and minimum values of LSPV and LIPV in a cardiac cycle all have statistically difference (P<0.05), meaning that the long diameter, short diameter and cross section area of LSPV, LIPV of patients with atrial fibrillation were larger than those of people without atrial fibrillation; (2) Between in group of atrial fibrillation and non-atrial fibrillation, the long diameter of the maximum and minimum values of RSPV, RIPV in a cardiac cycle all have statistically difference (P<0.05), meaning that the long diameter RSPV, RIPV of patients with atrial fibrillation were larger than those of people without atrial fibrillation;(3) There was no statistical difference in maximum and minimum value of short diameter of RSPV, RIPV between group of atrial fibrillation and non-atrial fibrillation (P>0.05), considering that short diameter of RSPV, RIPV in patients with atrial fibrillation and people without atrial fibrillation had no significant difference;(4) About the comparison of the maximum value of cross-sectional area of RSPV between group of atrial fibrillation and non-atrial fibrillation, t=2.298, P=0.024,0.01<P<0.05, we may consider that the maximum value of cross-sectional area of RSPV in patients with atrial fibrillation is greater than that of populations without atrial fibrillation; and the minimum value of cross-sectional area of RSPV in two group, t=1.90, P=0.061, P>0.05, there was no statistical difference between group of atrial fibrillation and non-atrial fibrillation in the minimum value of cross-sectional area of RSPV;(5) There was no significant difference in the maximum and minimum value of cross-sectional area of RIPV between group of patients with atrial fibrillation and without atrial fibrillation (P>0.05);(6) Maximum value and minimum values of four branch pulmonary vein to the pulmonary vein ostium index between group of people with atrial fibrillation and without atrial fibrillation were not statistical different (P>0.05), thinking of atrial fibrillation in patients undergoing pulmonary vein orifice index of pulmonary vein ostial shape with no atrial fibrillation having no significant difference;(7) Whether in group of AF or group of atrial fibrillation, pulmonary vein orifice of right pulmonary vein (RSPV, RIPV) were more partial to oval than that of left pulmonary vein (LSPV, LIPV), description of left pulmonary vein ostial shape, right pulmonary vein relative partial circle.3. Contrast analysis of pulmonary vein DSCT imaging before atrial fibrillation ablation and intraoperative pulmonary vein angiographyIn34patients with CT the recognition of pulmonary vein of136root, of which22were standard pulmonary vein anatomy (64.7%),5cases with separate orifices for the right side of pulmonary vein (14.7%),6cases of left common pulmonary vein opening (17.6%), and1case of left pulmonary vein shorter total stem and the right lung independent mixed venous variation (3%).Pulmonary vein angiography only recognition of pulmonary vein130in total, including3cases of patients with pulmonary vein angiography omission right side pulmonary vein (4branches,1cases of right2side pulmonary vein),2cases of patients with pulmonary vein angiography cannot identify the right inferior pulmonary vein. Between measurement of pulmonary vein diameter in DSCT pulmonary vein imaging and pulmonary vein angiography, using paired sample T test statistical to analyze the diameter of130branches of pulmonary vein ostium, P=0.115,0.089,0.169,0.077,0.518.0.893, P>0.05, the difference was not significantly statistical.4. The operation time of atrial fibrillation radiofrequency ablation guided by the traditional CARTO system and CARTO-Merge technology mappingIn20patients with atrial fibrillation using the traditional CARTO system mapping of radiofrequency ablation operation, the average operation time was (4.47±0.42) h,14cases of CARTO-Merge technology under the guidance of circumferential pulmonary vein ablation average operation time for the (3.68±0.35) h, using the independent sample T test, t=5.766, P<0.05, the difference was statistically significant.Conclusion1. Through the comparison of the incidence of the type and subtype of pulmonary vein anatomy variation, we found that there were no difference in patients with atrial fibrillation and without atrial fibrillation, meaning that the occurrence of atrial fibrillation are not related with the type and subtype of pulmonary vein anatomy variation, maybe the occurrence of atrial fibrillation due to its more complex electrophysiological mechanism;2. The diameter size of Pulmonary vein ostium in a heartbeat cycle showed periodic changing, its maximum and minimum value were at40%,80%phase. Accurate measurements of pulmonary vein diameter before atrial fibrillation ablation should be selected in the same phase of one heartbeat cycle; pulmonary vein diameter size and the occurrence of atrial fibrillation had certain relations, it still need to be further studied;3. DSCT can accurately assess the size and shape of pulmonary vein ostial, providing useful reference for measurements of pulmonary vein opening diameter before atrial fibrillation ablation and postoperative assessment of pulmonary vein stenosis;4. CARTO-Merge including DSCT reconstruction image with CARTO electrophysiological image, combined with intraoperative pulmonary vein angiography, can accurately grasp the anatomy of pulmonary vein, and provide help on the ablation the choice of Lasso electrode, but also greatly shorten the operation time, reduced radiographic exposure in patients. |
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